Halogen lamp

ABSTRACT

A lamp assembly is disclosed which includes a base, a lamp arm mounting adapter on the base for pivotally mounting a lamp arm thereto, with the lamp arm itself having a first pair of hollow support tubes mounted on the adapter for pivotal movement on a vertical axis in a generally horizontal plane and having a arm support pivotally mounted on their opposite ends for pivotal movement on a vertical axis on a horizontal plane. A second pair of arms having inner and outer ends are pivotally mounted on their inner ends to the arm support for pivotal movement about a horizontal axis in a vertical plane. A counterbalance spring is connected between the arm support and the second pair of arms and a lamp head is pivotally connected on the outer end of the second pair of arms for pivotal movement at least about a horizontal axis in a vertical plane.

This application is a division of application Ser. No. 133,319 filedOct. 8, 1993, now U.S. Pat. No. 5,396,409 which is a division ofapplication Ser. No. 795,339 filed Nov. 20, 1991, now U.S. Pat. No5,333,103 which is a continuation-in-part of application Ser. No.677,259, now U.S. Pat. No. 5,097,400, filed Mar. 29, 1991.

The present invention relates to a spring balanced arm assembly and moreparticularly to a spring balance arm and lamp head assembly adapted foruse with high heat intensity halogen lamp bulbs.

In recent years, the lighting industry has developed new forms of bulbsfor use in light fixtures. One such bulb which has been particularlysuccessful is the halogen light bulb for use in desk lamps or the likein place of conventional fluorescent or incandescent bulbs. Typicallythese bulbs have a 50 watt rating and use 12 volt current. These lampsare efficient and economical to use, but also produce a clear crispwhite light which is stronger and more intense than the light producedby conventional fluorescent or incandescent bulbs. One deficiency ofsuch bulbs is that in addition to the intense light produced, they alsoproduce intense heat.

Because of the high heat produced by halogen bulbs, it has only beenrecently that such bulbs have come to be used for interior lightingfixtures such as desk lamps. Their use previously has been limited toexterior fixtures in remote positions where they are not likely to betouched by the user or passers by. With the development of smallerbulbs, the desire to use these efficient and high quality bulbs in desklamps and the like has been increased. Unfortunately such lamps have notmet UL standards because the heat they produce makes it potentiallydangerous for the user to touch the lamp shade in which the bulb isplaced.

My prior patent application, identified above, is directed in part to alamp head assembly for a halogen lamp bulb which would meet UL standardsand provide a safe desk lamp. The construction of the counterbalancedarm used in the lamp of that application permitted movement of the lamphead in multiple directions, so that the lamp had a great degree offlexibility.

It is an object of the present invention to provide a further improvedspring balanced arm light fixture adapted to use high heat intensityhalogen bulbs and which has multiple degrees of freedom of movement forthe lamphead.

Another object of the present invention is to provide a lampheadassembly which may be safely used as a desk lamp fixture.

In accordance with an aspect of the present invention a lighting fixtureor desk lamp is provided which utilizes a UL approved lamphead assemblysuch disclosed in my prior U.S. patent application Ser. No. 677,259. Thearm support arrangement for the lamp head permits multiple degrees ofmovement of the lamp head about a base assembly. The fixture includes amounting adaptor for securing the lamp head assembly to any of a varietyof different kinds of bases while permitting the same freedom ofmovement as in the original desk lamp base.

The above, and other objects, features and advantages of this inventionwill be apparent in the following detailed description of illustrativeembodiment thereof, which is to be read in connection with theaccompanying drawings, wherein:

FIG. 1 is a perspective view of a lamp assembly constructed inaccordance with the present invention;

FIG. 2 is an exploded perspective view of the lamp shown in FIG. 1;

FIG. 3 is an exploded perspective view of the upper spring balanced armof the lamp of the present invention;

FIG. 4 is a perspective view of another mounting arrangement for thelamp of the present invention;

FIG. 5 is an exploded perspective view of the mounting adapterarrangement for the embodiment of FIG. 4;

FIG. 6 is a perspective view of another mounting arrangement for thelamp of the present invention;

FIG. 7 is a perspective view of yet another mounting arrangement for thelamp of the present invention;

FIG. 8 is a partial exploded perspective view of the lamp of thisapplication using a florescent bulb in lieu of halogen incandescentbulb;

FIG. 9 is a perspective view of yet another embodiment of the presentinvention;

FIG. 10 is a partially exploded perspective view of a still furtherembodiment of the present invention;

FIG. 11 is an exploded perspective view of the embodiment of FIG. 10;and

FIG. 12 is an exploded perspective view of the lamp head assembly usedwith the present invention.

Referring now to the drawings in detail, and initially to FIG. 1thereof, a spring balanced light fixture or desk lamp 10, constructed inaccordance with the present invention is illustrated. As mentionedabove, this lamp is particularly adapted for use with a halogen lowvoltage bulb.

Lamp 10 includes a circular support base 12 adapted to be placed on adesk or other work surface. A mounting post 14 extends upwardly frombase 12 and a pair of lower support arms 16 are pivotally mounted on thepost through a mounting adapter 18 as described hereinafter. An upperpair of support arms 20 are pivotally mounted to the ends of arms 16.These support arms may be spring balanced support arms, as describedhereinafter and in detail in U.S. patent application Ser. No. 677,259,or they may be supported without the use of the counterbalance spring ina shorter construction, as shown for example in the embodiment of FIG.12 of said application. In either event, a lamp head assembly 22 whichcontains a halogen bulb, is pivotally mounted on the upper ends of thearms 20.

In the illustrative embodiment of the invention, power is supplied tothe lamp through a transformer (not shown) which is adapted to beconnected to a source of 120 volt current. The transformer reduces thecurrent to 12 volts which is then supplied by a wire 26 to the lamp. Asdescribed hereinafter, using low voltage current in this way the arms16, 20 themselves serve as conductors, so that no internal wiring isnecessary in the arms.

Referring now to FIG. 2 of the drawing, it is seen that the support orbase 12 is a heavy circular metal disk which can sit on a desk or otherwork surface. The vertical hollow support post 14 is secured to base 12by screws 30 or the like. In this regard, the interior surface of post14 is formed with a plurality of small inwardly opening channels 32which can receive and hold the self-threading screws 30. Thus the screws30 pass through base 12 into the open lower end of the post 14 andthread themselves into cooperating channels 32 formed in the poststhereby to hold the post rigidly to the base.

The arm assembly of the light fixture of the present invention issecured to post 14 by the mounting adapter 18. The latter is designedand constructed to enable the lamp fixture to be secured to a variety ofdifferent support structures, in addition to the post 14, as describedhereinafter.

Mounting adapter 18 is formed of a rigid block of material having afirst section 36 which is somewhat larger than the smaller rear orsecond section 38. The latter has upper and lower surfaces 40, 42 formedthereon which are stepped down from the upper and lower surfaces of thesection 36 by arcuate steps or surfaces 44. Adapter section 38 also hasa pair of through bores 46 formed therein which receive the screws 48.The latter are engaged in open channels 33 formed on the interiorsurface of post 14 to secure the mounting adapter to the post.Preferably the mounting adapter section 38 is covered by a cap 50 whichis snap fit into the top of the post 14 after the adapter is securedtherein.

Mounting adapter 18 includes a pivot boss 52 on its front face 53. Thearms 54, 55 of the pair of arms 16 are formed of hollow metal tubeshaving bosses 56 received in their free ends. These bosses haveapertures formed therein which in turn receive a pivot bolt 58 which ismounted in boss 52.

As seen in FIG. 2, wire 26 extends up through arm 14, through a bore inmounting adapter 18 and its free ends are soldered or otherwiseconnected to metal washers 60 positioned on opposite sides of boss 52where they engage the bosses 56 of arms 54, 55. Thus, current issupplied from the wires directly to arms 54, 55.

The arms are secured pivotally to the pivot boss 52 by a fingernut 62which engages the threaded end of the bolt 58 when the lamp isassembled. This arrangement permits the first pair of arms 16 to pivoton a vertical axis in a horizontal plane as indicated by the arrow inFIG. 1.

The opposite ends of arms 54, 55 are pivotally mounted in an arm support66 which may be formed of a thermo plastic material. Arm support 66, asseen in FIGS. 1 and 2, has a first section 68 including a vertical bore70 formed therein and a second section or boss 72 having a horizontalbore 74 formed therein. The arms 54, 55 are pivotally connected to armsupport 66 by a pivot bolt 76 which is received in bore 70. Metalwashers 78 are provided on opposite sides of the arm support 66 totransfer current through metal adapters 80 to the upper arm assembly 20.These adapters fit in recesses 81 formed in the sides of support 66 andin the finally assembled lamp are concealed by snap fit covers 83.

The mounting arm support 66 can pivot on the bolt 76 to permit the upperarm assembly to pivot on a vertical axis about the bolt 76 in thehorizontal direction, as seen in FIG. 1. The assembly is retained inthis pivotal connection by the fingernut 62 secured to the lower end ofthe bolt 76.

The upper arm assembly 20 consists of a pair of arms 82 which are formedas hollow metal tubes. As seen in FIG. 2, these tubes have bosses 56mounted in their ends in the same manner as described above with respectto arm assembly 16. The lower pair of bosses 56 receive a pivot bolt 84which passes therethrough and through the bore 74 in arm support 66.Current is conducted from the lower pair of arms to the upper pair ofarms through the adaptors 80, previously described, and adjacent metalwashers 86. The arrangement is held assembled by the fingernut 62secured to the end of bolt 84.

Arm support 66 includes a pair of flanges 90 extending therefrom andhaving pivot holes 92 formed therein. To counterbalance the arm assemblya spring assembly 94 is connected to the arm support at the flanges 90.This spring assembly includes a rigid rod 96 pivotally connected by apin 98 to the arms 82 (See FIG. 3). The pivotal connection is preferablyformed by a pair of polycarbonate sleeves 100 press fit in openingsformed in the arms 82 and receiving the ends of the pin 98. The latterpasses through a bore formed in the upper end of the rod 96.

The lower end of the rod 96 is connected to a tension spring 102. Thelower end of the tension spring is connected to the free end of athreaded stud 104. The latter has a head pivotally connected by a pressfit pin 106 secured in the bore 92 of the flanges 90 in arm support 66.Preferably the spring 102 and a portion of the rod 96 are surrounded bya cylindrical tube 108 having a threaded lower end which threadedlyengages the stud 104. As a result, cylindrical tube 108, is held inplace and serves to conceal both the spring and the connection of thespring 102 to rod 96.

The upper ends of arms 82 have the sleeves or bosses 56 previouslydescribed mounted therein. A threaded bolt 110 having a head 112connects the sleeves to the lamp head assembly 22. The latter includes aneck 114 whose rear end has a bore 116 formed therein to receive theshank of the bolt 110 between the bosses 56 at the upper ends of thearms 82. The free opposite end of the bolt 110 is threadedly engagedwith the fingernut 65 to hold the assembly together and to provide anadjustable clamping force.

In order to transmit electric current to the lamp head assembly a pairof metallic washers 116' are provided in contact between the interfacesof the sleeves 56 and the adjacent surfaces of neck 114. The latter isformed of a plastic polycarbonate material and is non-conductive.Washers 116' are in electrical contact, by soldering or the like, withthe ends of wires within the neck which transmit the current to thesocket in the lamp head assembly in which a halogen bulb is mounted.

The lamp head assembly 22 is precisely as described in my aboveidentified U.S. patent application Ser. No. 677,259.

Neck 114 is generally cylindrical in shape and has an open free end 362.The socket 358 of bulb 360 is bolted to the free end 362 of the neck byscrews 364 or the like. Socket 358 is of conventional and of knownconstruction and has a pair of diametrically opposed ribs 366 formedthereon. These ribs are used to prevent inadvertent removal of the lamphead assembly as described hereinafter.

The cylindrical sleeve defined by neck 114 includes an annular flange367 formed therein as well as an annual groove 368 formed between theflange 367 and socket 358. These elements are used to control theposition of the lamp head assembly on the neck. Finally, neck 114includes a mounting boss 370 in which a control switch 372 is secured inany convenient manner.

The lamp head assembly is designed to insure that the surfacetemperature of the lamp head, particularly its peripheral edges and topsurface, which are most likely to be engaged by hand by the user, willhave relatively low temperatures, despite the high temperature of thebulb contained in the head. In addition, it is designed to prevent theuser from looking directly as an unexposed halogen bulb, since thebright light intensity of the bulb could be damaging to the human eye.

As illustrated in FIG. 12 lamp head assembly 22 includes a support ring380. This ring although illustrated as being circular, can have anydesired shape, such as oval or oblong, and the use of the word ring isnot intended to limit the configuration of this structure.

Support ring 380 is actually formed as two rings; an inner 382 and anouter ring 384 connected to the inner ring by three radial arms 386. Inaddition, a mounting sleeve 388 is provided integrally formed with rings382, 384. Mounting sleeve 388 has an internal bore 390 formed thereinincluding diametrically opposed internal grooves 392. The latter arecomplimentary to ribs 366 formed on the socket 358, so that the sleevecan only be put on or taken off of neck 114 when the ribs 366 andgrooves 392 are aligned. This will aid in preventing inadvertent removalof the sleeve and thus the lamp head assembly 22 from the neck 114.

In order to insure against inadvertent removal, a dual purpose stand-offpin 394 is provided. This pin has a threaded upper-end 396 threadedlyengaged in the outer ring 384 of ring 380, at the location of the sleeve388. The free end of the pin 394 enters the bore 390 of the sleeve, butthe shoulder formed between the pin and its threaded portion 396 definesa stop which limits the degree of insertion of the pin into the bore390. This arrangement permits the sleeve and thus the lamp head assemblyto rotate on the neck through 360°, but prevents the lamp head assemblyfrom being removed from the neck until the pin 394 is intentionallydisengaged from the ring.

The rear end of sleeve 388 has an undercut bore portion formed thereinwhich receives flange 367 of the neck 114. Flange 367 and the undercutbore are dimensioned such that the flange forms a stop against sleeve388 when the head is installed on the neck, so that the groove 368 isaligned with the position of the pin 394.

The inner ring 382 of support ring 380 includes an internal flange 410formed therein. The inner surface 420 of the inner ring 382 alsoincludes a plurality of vertical notches 422 formed in predeterminedlocations along its face above the flange 410. These notches and theflange 410 serve to permit mounting of the light reflector 424 of thepresent invention.

Reflector 424 is a generally semi-circular or parabolic reflector formedof a plastic or metallic material. Its inner face, i.e., the side facingthe bulb is preferably painted or coated with a light reflectivematerial. The reflector has a peripheral edge portion 426 from whichfour fingers 428 extend. These fingers are located to be received in thegrooves or notches 422 on the inner face of inner ring 382 where theywill rest on the upper surface of the inner flange 410. In addition, aportion of the reflector is cut out at 430 in order to accommodatesocket 358 and the neck of the lamp which enters the reflector.

Reflector 424 is perforated with small holes throughout its entiresurface. For clarity and convenience only some of the perforations areillustrated in the drawing, but it is to be understood thatsubstantially the entire surface is perforated with these small holes.

Lamp head assembly 22 includes a shade 440, preferably formed of atranslucent plastic material. In the illustrative embodiment of theinvention, the shade has a generally pyramidal shape in cross section,defined by a plurality of annular rings or steps. However, it is to beunderstood that the shape of the shade is decorative and can be formedin any desired shape. The shade has an opening 442 formed thereindesigned to accommodate the neck of the lamp when the shade isinstalled.

Shade 440 includes a central opening 444 formed therein which permitsheat to escape from the lamp head assembly, and in particular from thespace between the shade and reflector.

Shade 440 also includes an peripheral flange 446 which is generallycomplimentary to the shape and dimension of the flange 410 of the innerring 382 of support ring 380. Flange 446 has a plurality of notches 448formed therein.

The inner surface 420 of ring 382 includes five inwardly projectingfingers 450, which are adapted to overlie flange 446, when the shade isinstalled. Notches 448 in flange 446 are located to mate with andreceive the fingers 450. This arrangement permits the shade to bereceived within ring 382 so that the bottom surface 449 of flange 446rests on the fingers of shade 424 with the neck opening 442 slightlyoffset from neck 388. The shade is then rotated clockwise until four ofthe notches 448 overlie the fingers 450 so that the fingers enter thenotches and the bottom surface 449 of flange 446 rests directly onflange 410. In this position flange 446 is located below fingers 450 andfingers 450 are contained in notches 448. As a result, the shade islocked in the ring and cannot be removed. And, in that predeterminedposition, the opening 442 is aligned with neck 388.

With this construction, it is not possible for the user to look directlyat the bulb 360 through the shade or reflector, even at the points wherethe shade is mounted in the support ring. In addition, because thesupport ring 380 is formed as a double ring with a space between therings 382 and 384, the periphery of the ring 380 will be cooled byconvection air flow through the space between the rings. Thus, the outerring 384 is maintained at relatively low temperatures.

A transparent protective lens 460 is also provided in lamp head assembly22. This lens is preferably formed of lexan or other suitable plasticmaterial. The lens can be transparent, although preferably it may betextured in order to better disburse light from the bulb.

Lens 460 is secured to ring 380 by a peripheral support ring 462. Thisring includes an internal flange on which the lens sits.

The shape of the ring 462 is generally complimentary to but smaller thanthe shape of flange 410.

Ring 462 includes a plurality of ears or tabs 464 which extend radiallyoutwardly from the ring. These tabs are secured to the outer ring 384 ofthe lamp head assembly by screws 526 or the like. By constructing thelens support arrangement to the ring 380 in this manner, a smallperipheral space is formed between ring 462 and the flange 410 of thering 380 to allow air flow into the lamp head by convection for cooling.However, by this construction it is not possible to look directly at thebulb, even from the bottom of the lamp head assembly.

By this arrangement, it is seen that the lamp assembly of the presentinvention has multiple degrees of permitted movement, as indicated bythe arrows in FIG. 1. The whole assembly can pivot about the bolt 58 onthe mounting adapter 18 while the upper arm assembly 20 can pivot inboth a horizontal and a vertical direction about the arm support 66. Inaddition, the lamp head assembly 22 can pivot about the horizontal axisdefined by the bolt 110 and about the horizontal axis defined by neck114.

In another embodiment of the present invention illustrated in FIG. 4,the lamp assembly is substantially the same as previously described upto and including the mounting adapter 18. In this embodiment, the lampassembly is mounted to a base 130 which is formed as a track assembly. Aconnector arrangement 132 is provided consisting of two brackets 134,136 each of which has an inwardly turned flange 138 formed thereonadapted to receive the adjacent edges 140 of the tracks 142 formed inbase 130. Connectors 132 have integral extensions 144 formed thereinwhich are adapted to be received in an enlarged bore 148 formed inadapter 18 to provide a pivotal connection therebetween. The adapter 18is clamped between the connectors 132 by bolts 150 which are threaded byreceived between the connectors as illustrated in FIG. 5. By thisconstruction, another degree of pivotal movement is provided between thelamp assembly and the base as a result of the sliding connection definedby the connectors 132.

FIG. 6 illustrates another embodiment of the invention wherein thesupport post 14 is adapted to be mounted to a desk clamp 160. As seentherein a clip 162 is provided which has a pair of ears 164 formed onone end thereof defining a gap 166. The latter receives the tongue 168of the clamp 160 therebetween. The clip is then secured to the bottom ofthe vertical post 14 by screws 30 which, as described above, areself-tapping screws that thread into the channels formed on the interiorof the tube. This construction permits the same lamp assembly used inthe embodiments of FIGS. 2 and 4 to be mounted on the edge of a piece offurniture such as a desk or the like, without effecting the operation orconstruction of the lamp arm assembly itself.

FIG. 7 illustrates yet another embodiment of the invention wherein thesupport post 14 is received on a pivot filler piece 190. In thisembodiment the filler piece 190 is adapted to be received in a circularhole 192 formed in a desk 194 or the like. The filler piece has a bolt196 which extends downwardly therefrom and a butterfly clamp 198 isthreadedly engaged therewith to hold the filler piece on the desk by aclamping action. However, the filler piece is permitted to pivot in thehole 192.

The post 14 in this embodiment frictionally receives the ears 200 of thefiller piece 90 and is supported thereon. This permits another degree ofhorizontal movement of the entire lamp assembly about the pivot axis ofthe filler piece.

FIG. 8 illustrates an embodiment of the invention adapted for use with120 volt current and a florescent bulb rather than a halogen bulb. Inthis embodiment, the wire 26 extends through post 14 and through thehollow tubes of the arm assemblies to the neck 114 of the lamp. Thelatter has, instead of the head assembly 22 previously described, aconventional fluorescent bulb socket 210 formed therein for receivingthe bulb 212 previously described and a shade 214 which mounts on neck114 in any convenient manner. Accordingly it is seen that theconstruction of the present invention permits the same lamp constructionto be used with both halogen or fluorescent bulbs, and different powersupplies, without affecting the mechanical operation of the armassembly.

FIG. 9 illustrates yet another embodiment of the invention wherein alamp head assembly 230 is provided. In this embodiment the lamp head ispivotally mounted on another vertical axis 232 formed at the free end ofthe neck 114. Here again, yet another degree of pivotal movement isprovided to the lamp of the invention without affecting the operation ofthe remainder of the arm.

FIGS. 10 and 11 illustrate another embodiment of the invention which issimilar to the embodiments previously described. In this embodiment thelamp assembly 250 includes a base 12 as previously described and thesame support post 14 as in the previously described embodiments. Amounting adapter 18 similar to that previously described is alsoprovided. The adapter in this embodiment is somewhat differently shaped,as seen in FIG. 11, in that the pivot boss 52 in this case is defined bytwo flanges 252 extending from the front section 36 of the adapter.

In this embodiment of the invention the lower arm assembly 16 is formedfrom hollow arms 254 which are generally rectangular in cross-section,having pivot bosses 256 formed integrally at their ends. These pivotbosses are pivoted to the mounting adapter 18 by the bolt 258 (See FIG.11). The outer ends of the arms 254 are pivotally connected to an armsupport 260 by the bolt and nut assembly 262.

Arm support 260 has a pair of flanges 264 extending therefrom to whichthe upper rectangular arms 266 of the upper arm assembly 20 arepivotally mounted. The arms 266 are pivotally mounted to the flanges 264of arm support 260 by press fit pins 270 or the like, which permit thearms to pivot on a horizontal axis in a generally vertical plane.

The outer ends of the arms 266 are pivotally connected to a universaljoint mounting adapter 280. The latter includes a first section 282having flanges 284 formed thereon which receive and pivotally secure thearms 266 to the adaptor by means of the press fit pins 286 or the like.The universal joint adaptor 282 includes a second section 290 pivotallyconnected to the first section by the pivot bolt 292 or the like,corresponding generally to the pivot bolt 262 previously described.Finally, the neck 296 of a lamp head assembly 300 is pivotally connectedto the adapter section 290 by the fingerbolt and nut assembly 302. Asseen in the drawings, the adapter section 290 has a pair of flanges 304between which the rear end of the neck 296 fits, so that operation ofthe finger nut 302 provides a clamping action on the neck of the lamp.

The upper arm assembly in this embodiment of the present invention iscounterbalanced by a spring arrangement similar to that described inU.S. Pat. No. 4,080,530 the disclosure of which is incorporated hereinby reference. This spring assembly includes a tension spring 310 locatedwithin the lower hollow tube 266. The outer end of the spring is securedin any convenient or known manner to a hook 312 which engages the lowerpress fit pin 286 in the universal joint mounting adaptor 280. The rearend 314 of the spring is secured to a sliding shoe, as described in U.S.Pat. No. 4,080,530 which in turn is pivotally connected to a link 316.The latter may either have a hook formed on its end which engages theupper press fit pin 270 in the arm support 260 or it may have anaperture formed therein to receive that press fit pin when thecomponents are assembled. This construction provides a counterbalancingspring force to the lamp head assembly substantially in the mannerdescribed in U.S. Pat. No. 4,080,530. By this embodiment of theinvention many of the components of the original embodiment are providedin a lamp head assembly permitting for substantial interchangeability ofparts. In addition, a multiplicity of degrees of freedom of movement forthe lamp head assembly are provided.

Although illustrative embodiments of the present invention have beendescribed herein with reference to the accompany drawings, it is to beunderstood that the invention is not limited to those preciseembodiments, and that various changes and modifications may be effectedtherein by those skilled in the art without departing from the scope orspirit of this invention.

What is claimed is:
 1. A lamp assembly comprising a lamp support, a lamparm mounting adaptor mounted on said support including a pivot bossformed thereon; a first pair of hollow support arms having inner andouter ends with said inner ends being pivotally mounted on the pivotboss of said mounting adaptor for pivotal movement on a vertical axisand in a generally horizontal plane; an arm support pivotally mounted onthe outer ends of said first pair of hollow support arms for pivotalmovement on a vertical axis in a generally horizontal plane; a secondpair of arms having inner and outer ends with the inner ends thereofpivotally mounted on said arm support for pivotal movement about ahorizontal axis in a vertical plane; said mounting adaptor comprising agenerally rectangular mounting block having first and second mountingsections with said first mounting section being shorter in height thansaid second mounting section and positioned relative to said secondmounting section to defined opposed stepped surfaces on the mountingadaptor, said first mounting section having a first through bore formedtherein for selectively receiving a pivot pin; said second mountingsection having a front face and said pivot boss being formed on saidfront face; and a mounting support mounted on said lamp support andhaving a pair of spaced arms respectively received in said steppedsurfaces and a pivot pin extending therebetween, said pivot pin beingreceived in said first through bore of the adaptor, said second mountingsection having arcuate guide surfaces formed therein adjacent saidstepped surfaces and extending perpendicular thereto for cooperatingwith curved ends of the arms of the mounting support to allow pivotalmovement of the mounting adaptor on the pivot pin of the mountingsupport.
 2. A lamp assembly as comprising a base, a hollow elongatedtube mounted on said base, a lamp arm mounting adaptor mounted on saidtube including a pivot boss formed thereon; a first pair of hollowsupport arms having inner and outer ends with said inner ends beingpivotally mounted on the pivot boss of said mounting adaptor for pivotalmovement on a vertical axis and in a generally horizontal plane; an armsupport pivotally mounted on the outer ends of said first pair of hollowsupport arms for pivotal movement on a vertical axis in a generallyhorizontal plane; a second pair of arms having inner and outer ends withthe inner ends thereof pivotally mounted on said arm support for pivotalmovement about a horizontal axis in a vertical plane; said mountingadaptor comprising a generally rectangular mounting block having firstand second mounting sections with said first mounting section beingshorter in height than said second mounting section and positionedrelative to said second mounting section to defined opposed steppedsurfaces on the mounting adaptor, said first mounting section having afirst through bore formed therein for selectively receiving a pivot pinand at least a second through bore for receiving a mounting screw forsecuring said mounting adaptor to said tube; said second mountingsection having a front face and said pivot boss being formed on saidfront face; said hollow elongated tube having open ends and at least twointernal channels adjacent each other in generally parallel relation,said at least two internal channels having open end portions and beingadapted to receive mounting screws therein, said mounting block beingreceived in one end of said hollow elongated tube.
 3. A mountingassembly as defined in claim 2 including means for securing the otherend of said hollow elongated tube to the base, said means includingopposed interior channels formed in the tube and screws extendingthrough said base and engaged in said interior channels.
 4. A mountingassembly as defined in claim 3 wherein said base comprises a weightedcircular disk.